Surface acoustic wave device
AssigneeMurata Manufacturing Co., Ltd.
InventorsMichio Kadota, Takeshi Nakao, Masakazu Mimura
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Abstract
A surface acoustic wave device has a high electromechanical coefficient and reflection coefficient, and also has an improved frequency-temperature characteristic that is achieved by forming a SiO2 film on an IDT so as to prevent cracking from occurring on a surface of the SiO2 film so that desired properties can be reliably obtained. The surface acoustic wave device includes at least one IDT, which is composed of a metal or an alloy having a density higher than that of Al and is formed on a 25° to 55° rotation-Y plate X propagation LiTaO3 substrate, and a SiO2 film disposed on the LiTaO3 substrate so as to cover the at least one IDT for improving the frequency-temperature characteristic.
Claims32
A surface acoustic wave device comprising:
- a 25° to 55° rotation-Y plate LiTaO3 substrate having Euler angles of (0°, 115° to 145°, 0°);
- at least one IDT disposed on the LiTaO3 substrate and made of a metal having a density higher than that of Al;
- and
- an SiO2 film arranged on the LiTaO3 substrate so as to cover the at least one IDT.
24 A surface acoustic wave device according to claim 15, wherein the surface acoustic wave device uses a leakage surface acoustic wave primarily including a shear horizontal wave as the surface acoustic wave.
A surface acoustic wave device comprising:
- a 42° to 50° rotation-Y plate LiTaO3 substrate having Euler angles of (0°, 132° to 140°, 0°);
- at least one IDT disposed on the LiTaO3 substrate and made of a metal having a density higher than that of Al;
- and
- a SiO2 film arranged on the LiTaO3 substrate so as to cover the at least one IDT.
A surface acoustic wave device comprising:
- a 25° to 42° rotation-Y plate LiTaO3 substrate having Euler angles of (0°, 115° to 132°, 0°);
- at least one IDT disposed on the LiTaO3 substrate and made of a metal having a density higher than that of Al;
- and
- a SiO2 film arranged on the LiTaO3 substrate so as to cover the at least one IDT.
A method for manufacturing a surface acoustic wave device comprising steps of:
- preparing a 25° to 55° rotation-Y plate LiTaO3 substrate having Euler angles of (0°, 115° to 145°, 0°);
- forming at least one IDT on the LiTaO3 substrate using a metal having a density higher than that of Al;
- performing frequency adjustment after the IDT is formed;
- and
- forming a SiO2 film on the LiTaO3 substrate so as to cover the IDT after the frequency adjustment is performed.
Dependencies are inferred from the claim text.